Babywearing parents, help me choose between LennyLamb and Tula. I need the more breathable option, the one that can be useful for longer hours without giving me some backaches and the one that can be used for years (in terms of sizing).

I would go for Tula. They have this new line called Tula Coast. A part of its panel is made of mesh so you can be assured that it's breathable. Although, I gotta warn you. It's always out of stock whenever I check their website. You can check local dealers, though, like CEO Emporium, etc.